Presser-bar mechanism for sewing machines



Nov. 4, 1947;v F. F. zElER PRESSER-BAR MECHANISM FOR SEWING MACHINESFiled Nov. 19, 1945 5 Sheets-Sheet l Nov.44, 1947. F. F. Z'EIER`2,430,440

PRESSER-BAR MEGHANISM FOR SEWING MACHINES Filed Nov. 19,1945 5sheetssheet 2 PRESSER-BAR MECHANISM-FOR SEWING MACHINES Filed Nov. 19,1945 5 Sheets-Sheet 5 Nov. 4, 1947-. F. F. zEn-:R

`PRESSE'R-BR MECHANISM FOR SEWING MACHINES Filed Nov. 19, 1945 5sheets-sheet 4 album,

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NOV. 4, 1947. F, F, ZIER 2,430,440

' PRESSER-BAR MECHANISM FOR SEWING MACHINES Filed Nov. 19, 1945 5sheets-sheet 5 79 v 105 16? er .136 zal Patented Nov. 4, 1947 UNITEDSTATES PATE-.NT "DEFI-CE PRESSER-BAR. MECHANISM FORSE-WING MACHINESApplication November 19, 1945,tSeria1No. 629,363

23 Claims. 1 This invention relates to sewing machines and, moreparticularly, to means for raising a presserbag and/or an upperfour-motion feeding mechanism off the sewing machine work-support.

The usual `sewing machine is equipped with some type of a work-pressermechanism which is urged toward the work by means of a spring. vWorkingin cooperation with the work-presser or presser-foot mechanism for thepurpose of feedingthe work past the stitching mechanism is the usuallower four-motion feed-dog. This feed-dog commonly traverses anelliptical path which has its major axis substantially parallel to thesewing machine throat-plate. The feed- `dogfis positioned relative tothe throat-plate so that, when the feed-dog is traversing the upperportion of its path, the feed-dog teeth will project above the topsurface of the throat-plate. Therefore, during the first half of thefeeding movements of the feed-dog, when the dog is above the top surfaceof the throat-plate, the feed-dog .will move both upwardly and in thedirection offeed, thereby to grip the work against the presser-foot andactually lift the presserfoot and presser-bar a short distance. Duringthe latter half of the feeding movement, the feed-dog moves bothdownwardly and in the direction of feed before dropping below the topsurface of the throat-plate. The downwardly spring-biased presser-footand the presser-bar drop with the feed-dog until the down-movement ofthe work is arrested by the throat-plate. The work then remainsstationary while the feed-dog returns below the level of the upper faceof the throat-plate to its initial position' to begin another feedingstroke. 'Ilhese engagements of the feed-dog with the work usually occuronce for each stitch made by the machine, and the presser-bar and footmust rise and fall with the feed-dog once for each stitch.

Due to the movement of the feed-dog in the direction of feed, the workis drawn under the sole portion of the presser-foot, thereby introducinga sidewise thrust which sets up frictional forces between thepresser-bar and its bearings and thus this frictional force, coupledwith the natural inertia of the usual presser-bar, tends to prevent thepresser-bar from returning quickly to its lower position when thefeed-dog moves downwardly.

As the speed of a sewing machine is advanced, it |becomes increasinglydifcult to return the presser-foot quickly and forcibly down upon the-work at the end of the feed-advance stroke of the feed-dog. At thesehigher speeds of operati-on oftherma'chine, thefriction between thepresser-bar and its bearings isrincreased .duetto the increased speed.ofthe Work under the presser-'foot `sole portion, and this (friction,coupled with the inertia of the machine parts builds up to the `extentlthat the spring which is used-to return or lower thefpresser-b'ar:cannot function to lower completely the presser-foot between con-Vsecutive `Work.-disengaging Vand work-engaging movements of .thefeed-dog.

'Sewing vmachines having Yan upper four-motion feeding mechanism of the:character known `as the alternating presser type` alsopresentsubstantially: the same. .problem `as that hereinabove discussed. .Inthis type of mechanism, there is employed an automatidpresserandfeeding-foot .lifting mechanismwhich fisnormally dependent upontheresistance imposedlby thework or its 4support to thedownward movementof either .the presser-foot or feeding foot, in orderto .provide afulcrum for lifting the other of said members. Therefore, if any.inertiaVor cramping of the parts occasions a sufficient resistance before4either of said members in its descending movementireaches the work,.the necessary fulcrum will be untimely provided and neither ofsaidmembers will engage the work with the requisite `pressure toinsure aproper Work-feeding action. -Theliabilitynf imperfect operation offeeding mechanisms of vthis character increases withthe speed ofoperation of the machine, due ina largemeasure rto inertia ofthe `partsand also becausethe spring which depressesthe .presser and feeding footelements cannot recover with sufficient rapidity to overcomethe upwardmovements'thereof. At extreme vhigh speeds, a degree of Ainefoiencymaybe reached `wherein neither the presser-foot nor the feeding-footperceptibly engages the work.

One method Vof overcoming the above discussed difficulties is toprovidethe mechanism, whether it be of the usual simple presser-bar or olf theupper four-motion feeding type, with a spring capable ,of exerting aforce materially greater 4than `that .heretofore used. Although theaddition of this spring helps to obviate the one difiiculty, it wasfound `that thenecessary force of the spring required excessive manualeffort `to lift thepresser-footoff the work. Even if the machineoperator could exert the requisite amount of force to lift thepresser-bar, she would soon tire `of such arduous work. It has beenfound that an operator can, with comfort, continue to `operate apresser-bar lifting device if the maximum 'force required does notexceed ten pounds. However, many of the present type sewing machinesrequire a spring force of about fty pounds in order to urge thepresser-foot against the work with the requisite force to properly feedthe work at all different speeds of operation of the machine.

It is, therefore, an object of this invention to provide a sewingmachine with presser-bar lifting means which will require a minimum offorce to operate.

Another object of this invention is to provide an improved means forapplying to and removing spring pressure from a work-presser mechanism.

With the above and other objects in View, as will hereinafter appear,the invention comprises the devices, combinations and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the several`features of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

Fig. 1 represents a rear side elevation of a sewing machine in which thepresent invention is incorporated.

Fig. 2 represents a top plan View, partly in section, of the presentmachine.

Fig. 3 represents a left side elevation of the sewing machine, showingthe stitching and feeding mechanisms with the bed and work-supportingplate in section, and with the needle in its uppermost position.

Fig. 4 represents a left side elevation of the stitching and feedingmechanisms as removed from the sewing machine frame and with the needlein its lowermost position.

Fig. 5 is a detail view, in elevation, of the feed-lift crank in itsraised or inoperative posi. tion, with the lock-pin device sustainingthe crank in this position.

Fig. 6 represents a sectional View of the upper feeding and stitchingmechanism taken substantially along line 5--6 of Fig. 1.

Fig. 7 represents a sectional View of a portion of the feedandpresser-bar actuating mechanisms taken substantially along line 1-1 ofFig. 3.

Fig. 8 represents a sectional view showing a portion of the presser-barwith its associated elements and taken substantially along line 8-8 ofFig. 6.

Fig. 9 represents a sectional View showing a feed-bar lifting means andtaken substantially along line 9-9 of Fig. 6.

Fig. 10 represents a sectional view showing the presser-liftingmechanism in its normal position and taken substantially along lineIfI--IU of Fig. 2.

Fig. 11 represents a detailed view of that Geneva stop mechanism whichactuates the spring-disengaging toggle mechanism.

Fig. 12 is an illustration in side elevation of the presser-liftingmechanism at that point in its cycle at which the presser spring isfully relaxed.

Fig. 13 represents an enlarged detailed view in side elevation of thefulcrum member and the presser-bar lifting arm which is engaged thereby.

Fig. 14 is an illustration of the presser-lifting mechanism at thatpoint in its cycle at which the presser-bar and top feed-bar are fullyraised 01T the work.

Fig. 15 represents a detailed view of a portion of the presser-liftingmechanism taken substantially along line I5-I5 of Fig. 1 and showing the4 mechanism at that point in its cycle corresponding to that illustratedin Fig. 12.

Referring to the drawings, the invention is embodied in a sewing machinehaving a frame comprising a bed I6 from one end of which rises astandard I1 of an overhanging bracket-arm I8 terminating in a head I9.Journaled for rotation within this frame is a main-or arm-shaft 2Dcarrying at its outer end the usual belt-driven balance-wheel 2I and atits inner end a counterbalanced needle-bar actuating crank 22. Shaft 20is connected by a clip-belt 23, herein shown incompletely, to abelt-pulley 24 fast upon the outer end of a lower mainor bed-shaft 25journaled for rotation in the bed I6, the ratio between the shafts 20and 25 being one-to-one.

Actuated by the bed-shaft 25 is the usual lower four-motion work-feedingmechanism, including a feed-dog 25, and the looper mechanism including achain-stitch looper 21. For the sake of brevity, a detailed descriptionof the four-motion feeding mechanism will not be given herein, inasmuchas the same is fully described and claimed in my U. S. Patent No.2,292,258, Aug. 4, 1942.

With regard to the looper mechanism disclosed in the drawings, it willsulce to say that the looper 21 is preferably of the two motion typehaving loopseizing and shedding movements only in the line of feed, thelooper advancing to seize the needle-loop in a direction opposed to thedirection of feed.

Referring now to the mechanism within the machine-head I9, it will beseen in Figs. 1, 3 and 4 that a needle-bar actuating link 28 ispivotally mounted upon the crank 22 by means of a screw 29. The lowerend of the link 28 is apertured to receive a pin 30 integral with asplit collar 3I clamped upon the usual needle-bar 32. Carried at thelower end of the needle-bar 32 is a suitable needle 33. Through themechanism just described the needle-bar 32 is reciprocated endwise inproper timed relation with the complemental looper 21 to producechain-stitches.

The needle-bar 32 is journaled in bearing members 34 and 35 projectingfrom the needle-bar frame 36 which is provided with a horizontallyprojecting fulcrum-rod 31 journaled within the lug 38 of the machinehead I9.

The needle-bar-frame 36, in the machine illustrated, is oscillated intimed relation with the four-motion feed-dog 26 through mechanismcomprising a rock-lever 39 (see Fig. 1) preferably clamped at its lowerend 40 upon the end portion of the fulcrum-rod 31. At its upper end, therock-lever 39 is pivotally connected, by means of a bolt 4I and nut 42to one end of a relatively short pitman 43 formed at its other end witha strap 44 embracing an adjustable eccentric 45 secured to rotate withthe arm-shaft 29. It will be understood that as the arm-shaft 29 isrotated, the eccentric 45 actuates the pitman 43 which in turn operatesthe rock-lever 39 to oscillate the needle-bar-frame 36 about the axis ofthe fulcrum-rod 31. The amplitude of oscillatory movement imparted tothe needle-barframe is dependent upon the amount of eccentricity of theeccentric 45 and, in order to vary the amplitude of the oscillatorymovements of the needle-bar frame to harmonize with the stitch-length towhich the lower feeding mechanism is set, the eccentric is madeadjustable. A complete description of this type of adjustable eccentricmay be found in the U. S. patent of W. Myers, No. 2,128,031, Aug. 23,1938. For a more detailed description of the present type of needlebarmechanism, reference may be had to my U. S. Patent No. 2,329,681, Sept.14, 1943.

Referring particularly to Figs. 3 and 4, the needle-bar frame 36 has avertically apertured bearing lug 116 formed thereon adjacent the bear- 5ing portion 35. Slidably mounted within this bearing lug l' is a topfeed-bar 41 carrying at its lower end a feeding foot 98 which is adaptedto cooperate with the needle 33 and the lower feed-dog 26 in the feedingof the work over the bed-plate 49. Since the feed-bar 41 is carried bythe needle-bar frame 36, the latter element will impart the sameamplitude of vibrating motion in the line of feed to both the needle-bar32 and the top feed-bar 41.

The upper end of the top feed-bar d1 is provided with a cross-pin 59which is slidingly received within the forked free end 5I of asubstantially horizontally disposed feed-lift lever 52. The conned endof the lever 52 is pivotally mounted upon a fulcrum-pin 53 which issecured within the lower rear portion of the machine head I9.

In order to prevent the feed-bar 41 from turning about its longitudinalaxis, the top portion thereof is provided with a pair of cheeks 59 whichcarry the cross-pin 50 and which embrace the forked portion 5I of thelever 52.

The machine head I9 is provided with a Vertically disposed stationarybearing member 55 in which a presser-bar 55 is slidingly mounted so asto be located slightly rearwardly of the top feed-bar 41 and out of theline of feed at that side of the line of feed nearest to the machinebracket-arm I 9. A usual type of presser-foot 51 is carried by the lowerend of this presser-bar 55. Formed in the up'er portion and between theends of the presser-bar 55 is a slot 58, Fig. 8, A

adapted to receive the free end of one arm 59 of a bell-crank leverwhich is pivotally carried by and at the center of percussion of thefeedlift lever 52.

This bell-crank lever comprises the above noted arm 59 carried by oneend of the pivot pin 69, to the other end of which is secured, by meansof a screw 6I, a second arm 52 which is pivotally connected by a pin 63to the lower end of a link 915. The pin 50 passes through the aperturedbearing portion 65 of the lever 52 whose center of percussion lies alongthe axis of bearing portion 55.

The upper end portion of the link 64 is connected by means of a pin 56to an actuating crank 91 carried by one end of a rock-shaft 68 which isjournaled in bearing lugs 59 and 1i) provided on the machine bracket-armI3 and h'ead I9, respectively. T'he rock-shaft 66 is disposed inparallelism with the needle-bar actuating shaft 29.

Secured upon the opposite end portion of the rock-shaft 68, by means ofscrews 1l, is a short crank 12 carrying a pin 15 which is pivotallye-mbraced by the forked end of a pitman 14 whose other end terminates inan eccentric strap 15. Strap 15 embraces an adjustable eccentric 15secured to rotate with the arm-shaft 29. It will be understood that asthe arm-shaft 29 is rotated, the eccentric 16 actuates the pitman 14which, in turn, imparts rocking movements to the rock-shaft 58 throughthe medium of the crank 12. The amplitude of these movements may bevaried by adjusting the throw of the adjustable eccentric 15. For a morecomplete description of an adustable eccentric of this type, referencemay be had to the U. S. patent of A. H. De Voe, Reissue No. 14,218, Nov.28, 1916.

Pressing downwardly upon the feed-lift lever 52, at a point between thebell-crank pivot point and the forked end 5I thereof, is one end of aspring-biased blade-lever 11 which is located outside of and rearwardlyadjacent to the machine bracket-arm I8. The other end of this lever 11is biased upwardly by means of a coil spring 18 which is operativelyconnected to an arm l'I9 mounted upon the bracket-arm I9. The lower endof the spring 18 is pivotally connected to the lever 11 by means of abolt 80 and nut BI. As illustrated more particularly in Figs. 6, 9 and10, lever 11 is fulcrumed adjacent to the feed-lift crank 52 upon aknife-edge 82 of a-fulcrum-piece 93 extending from a, stub-shaft 84which is rockably mounted within an aperture 35 (Fig. 6) formed in thelower portion of the machine head I9. In order to prevent thespring-biased lever 'l1 from exerting any side thrust upon the feed--lift lever 152, a steel ball 89 is held, by means `of a sheet metal cage81, between said lever 11 and crank 52. The cage 81 is secured to thecrank 52 by means of screws 88.

Referring particularly to Figs. 6 and 9, the lever 11 is apertured so asto afford clearance for a guide-pin 89 projecting upwardly from theshelf portion 99 of the head I9 and extending through the forked end ofa guide-arm 9| which is clamped -by means of a screw 92 to the upperreduced portion of the presser-bar 59. Thus the presser-bar 56 isprevented from turning about its longitudinal axis and at the same timethe pin 89 prevents the lever 11 from moving sidewise.

The oscillatory motions of the above noted rockshaft 58 cause thebell-crank lever 59, 92 to swing in a vertical plane about its pivot pin50 in the feed-lift lever 52, so that the arm 59 thereof successivelytends to lift and depress the presser-bar 55. When the presser-bar 56 isdepressed, however, its presser-foot 51 engages the throat-plate 93, orthe work carried thereby, and further movement of the bell-crank levercan only result in raising the pivot point thereof, which latter actionwill, of course, raise the forked end 5I of the feedlift lever 52 withthe consequence that the top feeding-foot 48 is lifted clear of thethroat-plate 93, as is illustrated in Fig. 3. Continuous oscillation ofthe rock-shaft 68 will, therefore, cause the presser-bar 56 and the topfeed-bar 41 alternately to rise and fall, and the spring-biased lever 11being in continuous engagement with the feed-lift lever 52, it will haveits force transmitted to either the presser-bar or to the top feed-bar,depending upon which one of the two elements is in engagement with thethroat-plate or work. 'I'he motions of the rock-shaft 68 aresynchronized with those of the needle-bar 32 so that the usual compoundfeeding motions will be effected.

Adjustment of the rock-shaft actuating eccentric 16 will effectadjustment in the amplitudes of the relative vertical movements impartedto the presser-bar and top feed-bar.

As hereinabove noted, one end of the lever 11 is pivotally secured tothe coil spring 19 by means of the bolt 89. Referring more specificallyto Figs. 1, 2, and 10, the lower end of the spring 18 is secured to thelower cup-shaped member 94 which is telescopically tted within the upperand reversely directed cup-shaped member 95 rwhose upper portion has athreaded rod 96 projecting upwardly therefrom. Clamped upon the rod 96is a split collar 91 having a threaded bolt portion 98 extendinglaterally therefrom. Pivotally embracing the bolt 98 is the arm 10 heldupon thev bolt by means of nuts 09. rIhe upper end of the spring issuitably secured to the member 95, thus to bias the lever 11 upwardly.The two cupshaped members and 95 form a substantially airtight unitwhose purpose is to dampen the violent spring vibrations which wouldotherwise occur when the spring 'l0 passes through its critical phases.A rubber spacer |00 is disposed within the spring to limit lateralvibrations thereof.

The applied pressure of the spring 18 may be varied by shifting the rod95 relative to the clamp collar 91, when loosened, by means of astop-nut |0| which is carried by the threaded upper portion of the rod90. The clamping screw |02 is used for tightening the collar d1 aboutthe rod S8 in the set position of the collar.

Referring particularly to Fig. 10, the fulcrum point 82 of thespring-biased lever 11 is so located that the lever is of the iirstclass; the portion thereof extending forwardly of the fulcrum point .82being very much shorter in length than that portion which extends fromthe lever pivot point at 80 to the fulcrum point at 82. By means of thelever, or multiplying means 11, the amplitude of vertical movement ofthe feed-lift lever 52 is, in a preferred form of the device, multipliedby ve at the effective end of the lever 11, thus to impart to the levera force ve times greater than the spring would impart thereto if it wereacting directly upon the lever. Thus, a relatively light spring isadequate for supplying the proper pressure to the presser-foot and topfeeding foot. Tests have proven that by using such a multiplier,superior results have been attained as compared to the results attainedwhen using the same top feeding and presser elements but with a springhaving about ve times the stiffness of spring 11 and applied to beardirectly upon the lever 52. Apparently there is much advantage to begained by using a light weight spring coupled with a multiplier ascompared to using a heavier weight spring which is applied directly uponthe lever 52. These tests have shown that the use of the presentmultiplier mechanism completely obviates the tendency of the feet d8 and51 to flutter when the machine is operating at a high rate of speed. Itis an advantage to use a spring having a high natural frequency for thispurpose.

From the above description it is to be understood that through themedium of the lever 11, the spring exerts a tremendous force upon thelever 52. To raise the feet 08 and 51 against this force would require arather awkward and impractical mechanism, or one that would require theapplication of a manually exerted great force. The present invention isapplied to the above described machine for the purpose of providing amanually operable presserand top feed-bar lifting means designed to keepat a minimum the lifting force required. Broadly, these means compriseelements adapted, under treadle-controlled action, to render the coilspring 18 ineffective and to relatively shift the knife-edge fulcrum 82and the spring-biased lever 11 to permit the presserand feed-bars freelyto be raised of the work.

.Specically the present lifting mechanism comprises a self-containedframe member |03 secured to the standard l1 by means of the screws |04which are threaded directly into the standard. Projecting inwardly fromtwo sides of the member |03 is an edge portion |05 (Fig. 2), whichVfunctions partially to enclose the mechanism contained within the unit,Upon this frame are mounted two sets of Geneva stops geared together inorder to provide a series of successive motions all produced by a singledownward movement of the usual foot-actuated treadle (not herein shown)which is connected to the Geneva stops by means of a chain |06 and apivoted arm or manually operable member |01, to which the chain issecured by means of a stud |08. The arm |01 is pivotally carried upon ashaft |09 entering an aperture ||0 provided in the frame |03. The freeend portion of the arm |01 has a lip portion upon the end of which iscarried, by means of screws H2, a segment-gear ||3. This segment-gear||3 meshes with a gear I Ill mounted upon a rockable stub-shaft |5 andsecured by means of screws ||6 to a Geneva driving element ||1 which inturn is secured upon the shaft ||5 by means of a set screw ||8.

Carried by one end portion of the element |1 is a pin ||9 adapted toslidingly enter a slot |20 of a Geneva driven element |2| which ismounted, by means of a set screw |22, upon a rockable shaft |23journaled in ,a portion |24 of the frame |03 (see Fig. 15). Mounted uponthat end of the shaft |23 remote from the element ||1 is a crank |25carrying at its outer end portion a pin |26 upon which is pivotallymounted the lower end of a substantially upright link |21. The upper endportion of the link |21 carries a pin |28 which connects the link to atoggle joint comprising the double arms |29 and |30. Arms |30 arepivotally mounted upon a stud |3| carried by the frame |03 and arms |29are pivotally connected, by means of a pin |32, to arm |33 which ispivotally mounted upon a shoulder stud |34 carried by the frame |03. Thehereinabove noted arm 19 is integral with arm |33 and therewith forms abell-crank lever which is connected to the spring-carrying rod 96.

From the above description, it is to be understood that, responsive toan initial downward movement of the treadle-chain |06, the segment gear||3 will turn gear H4, thereby carrying the pin ||9 upwardly to eilectan upward movement of the slotted portion of the element |2|. As thedriven element |2| turns about its axis, it rocks the shaft |23 which,in turn, will rock the crank |25 upwardly and elevate the link |21. Thisupward movement of the link |21 will flex the toggle joint, thus toswing the arm 19 of the bell-crank lever downwardly to the extent thatthe spring 18 will be completely relaxed. rIhis completely removesdownward force upon the feet 08 and 51. By using a forcemultiplyingmeans such as the present toggle joint for rendering the spring 10ineiective, little force is required to be exerted upon the link |21.

Fig. 10 illustrates the present lifting mechanism in its normalcondition, with the toggle arms |29 and |30 in their straightenedposition and with the spring 18 fully distended, to the end that itexerts its pressure upon the ball 86. Fig. 1'2 illustrates thismechanism when the toggle is broken and the spring is completelyrelaxed.

Pivotally mounted upon the stud |34 and adjustably secured to arm 10, bymeans of a set screw |35, is an arm |35 having a cam portion |31 thereonwhich is adapted to engage a plunger 30 for the purpose of releasing thetension between the disks |39 of a usual type of needlethread tensionunit. The cam is adapted to engage the plunger only when the arm |36,swings to the position shown in Fig. 12.

Although the initial downward movements of the chain |06 and arm |01were effective to relax the spring 18, it will be seen from Fig. 12 thatthere is very little clearance between the lever 11 and the fulcrumpoint 82, and as a consequence the fulcrum point 62 must be removedbefore the presser-bar 56 can be raised any appreciable distance abovethe throat-plate. Therefore, mechanism has been provided in the presentdevice for the purpose of swinging this fulcrum point out of the path oflever move ment.

Referring to Fig. 12, it will be seen that further movement of thetreadle chain will not move the bell-crank and coil spring 18, as thepin |I9 will merely swing clear of the slot |26 and the circular portion|46 of the driver ||1 will engage the corresponding circular hollow I4|provided in the driven element I2I and thus lock the element 42| in theposition shown.

Referring t Figs. l, 10, 15 and 11, the gear I|4 meshes with a secondgear |42 which is mounted upon one end of a stub-shaft |43 by means of ascrew |44. The stub-shaft |43 carries at its other end a Geneva, drivingelement |45 carrying a pin |46 which is adapted to enter a slot |41 of aGeneva driven element |46 which is pivotally mounted upon a stud |46carried by the frame |63; Provided upon the driven element |48 is asegment gear portion |50 in'mesh with a rack portion II provided' on a,rock-bar |52 which is slidably mounted within an apertured lug providedon the frame |63 and the aperture |54 formed in the head I9.

The forward end portion of this rock-bar |52 is also provided with teeth|55 adapted to mesh with gear teeth |56 provided on the end portion ofthe above noted stub-shaft 84 which carries the knife-edge 82Y and,therefore, any forward linear movement thatl may be imparted to therock-bar will be effective to rotate the stub-shaft 64, thereby toremove the fulcrum point from the spring-biased lever 11for the purposeof providing proper clearance between the lever 11 and the fulcrum sothe lever 52 may be freely raised.

Threaded into the fulcrum-piece 83 of the stub-shaft 64, at a pointeccentric to the axis of rotation thereof, is a screw l|51 of which anexposed shoulder portion |58 (see Figs. 6, 9 and 13) enters a slot |59provided adjacent one end portion of a sheet metal arm |66, the otherend cf which is pivotally secured to the under body of the machinebracket-arm I8 by means of a screw |61. The free end of the arm |66,adjacent the slotted portion thereof, is bent to form a lip E62underlies the guide-arm 9| carried by the presser-bar 56. A turningmotion of the stubshaft S4', therefore, throws the screw |51 in anarcuate path, thereby raising the free end portion 0f the sheet metalarm |66 which, in turn, lifts the presser-bar 56. This upward movementof the presser-bar lifts the top feed-bar 41 also, through the medium ofthe bell-crank lever 59, 62 which is -pivotally carried bythe feed-liftlever 52.

Referring to Fig. 13, it is ,to be understood that the slot |56 isarcuate in shape and disposed at an angle such that an initial turningmovement of the stub-shaft 84, in the direction indicated, will beeffective to drop the arm |66 slightly, thus to introduce a slightJ timedelay before the arm is lifted, to the end that the fulcrum point 82will 10 be removedv from the lever 11 before the bar 56 is raised.

Referring now to Fig. 10, which illustrates the lifting mechanism in itsnormal position, the driving element |45 is provided with a circularportion |63 which engages the circular hollow |64 of the driven element|48 for the purpose of locking the latter element in its initialposition.

The cycle of the first Geneva stop mechanism, which is adapted to relaxthe spring 16, has been heretofore described, and from an inspection ofFigs. 1D, 12 and 14, it will be seen that this first Geneva stop issynchronized with the second Geneva stop which is adapted to shift thefulcrum and lift the presser mechanism. Fig. 12 illustrates the liftingmechanism at that point in its cycle where the first Geneva stop hascompletely relaxed the spring 18 but the driver |45 of the second Genevastop at this point has rotated from its initial position (shown in Fig.l0) to a position where its pin |46 is about to enter the slot |41 ofdriven element |46, thus to initiate movement in this latter element. Itis to be understood, therefore, that no movement can be imparted to theelement |46 until the spring 16 is relaxed completely.

Referring to Fig. l2, the spring is relaxed and, therefore, furthermovement of the chain 66 will be effective to: urge the pin |46 intoslot |41 for the purpose of -driving the element |48 in a clockwisedirection, to the end that its teeth |56' will urge the rock-barforwardly and actuate the stubshaftV 84 as above described. During thisportion of the cycle, it willbe noted that pin H9 works c lear of theslot |26 and thus the element will continue to turn without rotating'theelement I2 I.

From the above description, it will be understood that a single downwardmovement of the chain |66 will producethree successive .actions withinthe lifting mechanism. The spring 18 `is first relaxed by the action ofthe first Geneva stop, the second Geneva then is activated to shift therock-bar forwardly thus to raise the ulcrum point, and due to theexistence of the arcuate slot |59, the lifting of the presser-bar 56 isdelayed until the fulcrum is out of engagement with the lever 11.

Upon releasing the manually applied force exerted on the treadle chain|66, the above described mechanism will return to its normal position(shown in Fig. 10) under the force of a pair of tension springs |65 and|66 which are eective to retension the coil spring 16. At their upperends, both springs |65 and |66 are secured to the frame |63 by means ofa screw' |61, and at their lower ends they are secured to the upperportion of a flexible steel band |66 which is fixed, by means of a screw|69, to an eccentric hub |16 carried upon an end of the shaft II5. Asstub-shaft I I5 also carries the gear I4, it will be understood that asthe eccentric hub |16 is rotated in a clockwise direction it will placethe springs |65 and |66 under increased tensionso that they will urgethe shaft ||5 to rotate in an opposite direction when the force isremoved from the chain |66. These springs are of sufficient strength todrive the entire mechanism back to its initial position as they actthrough the toggle links |29 and |36 which are designed to havesuflicient mechanical advantage to overcome the force of the springs 1B.It is to be noted that the hub |16 is shaped in a manner such that theinitialA movement thereof,vin a clockwise direction from the positionshown in Fig. l0, will impart to the springs |65vv and |66 themajorportion of the increased 11 tension, and that the further movementof the hub will impart a lesser degree of tension to the springs. Bymeans of this hub construction, no undue tension will be imparted to thesprings.

The presser-bar and top feed-bar may be locked in their respectiveraised positions by means of a vertically disposed lock-pin mounted in alug |1| provided on the machine head |9. This lock-pin device comprisesa hollow stationary sleeve |12 fitted into the lug |1| and securedtherein by means of a set screw |13. Slidingly mounted within the sleeve|12 is a cylindrical pin |14 having a slab-sided upper portion |15 whichenters a corresponding slot |16 provided within the upper portion of thesleeve |12. This pin |14 is adapted to be raised manually against theforce of a small coil spring |11 and then turned so that the slab-sidedportion of the pin is out of phase relative to the slot |16, whichlatter action is effective to lock the pin in its raised position asshown in Fig. 5; As the pin is located beneath the top feed-lift lever52 it is effective, in its raised position, to prevent the lever andconsequently the presser-bar and top feed-'bar'from returning to theirnormal lowered position.

The present device, therefore, provides a means whereby the presser-barand/or the top feeding mechanism of a sewing machine may readily beraised above the work with the expenditure of a minimum amount of energyby the operator.

Furthermore, this device enables the pressermechanism to be equippedwith a spring of requisite strength, las the device provides for easilyrelaxing any spring'that may, with advantage, be applied to'asewing'machine vpresser-mechanism.

Having thus set forth the nature of the invention', what I claim hereinis: l

Y1. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-bar, a lever having one end portionthereof in operative engagement with said presser-bar, fulcrum means inengagement with an intermediate portion of said lever, a spring inengagement with the other end portion of said lever and being effectiveto bias said presser-bar toward said work-support,'means to removeitheYforce of said spring from said presserbar, and means operable upon theuremoval of said spring force from said'presser-bar for shifting saidpresser-bar away from'said work-support.

2. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a vpresser-bar, a lever having one end portionthereof` in operative engagement with said presser-bar, fulcrum meansin'engagement with an intermediate portion of said lever, a spring inengagement withthe other' end portion of said lever and beingeffectiveto bias said presser-bar Ytoward said work-support, andmanually'operable means upon an initial movement of which the force 'ofsaid spring is removed er-bar toward said work-support, means forremoving the force ofr said spring from said presser-bar preparatory toshifting said presser-bar,

means for moving said fulcrum means out of en- 5/ gagement with saidlever, and means for shift- Iing said presser-bar away from saidwork-support.

4. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-bar, a lever having one end portionthereof in operative engagement with said presser-bar, a fulcrum inengagement with an intermediate portion of said lever, a spring inenga-gement with the other end portion of said lever and being effectiveto bias said presser-bar toward said work-support, means for removingthe force of said spring from said presser-bar preparatory to shiftingsaid presser-bar, and means actuated by said rst mentioned means for'shifting said presser-bar away from said work-support upon the removalof said spring force from said presser-bar.

5. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-bar, a lever having one end portionthereof in operative engagement with said presser-bar, a fulcrum inengagement with an intermediate portion of said lever, a spring inengagement with the other end portion of said lever and being effectiveto bias said presser-bar toward said work-support, means for moving saidfulcrum out of engagement with said lever preparatory to shifting saidpresser-bar, and means actuated by said first mentioned means forshifting said presser-bar away from said Work-support.

6. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-bar, a4 spring for pressing saidpresser-bar toward said work-support, a manual control member, meansincluding a toggle mechanism connected with said member for removing theforce of said spring from said presser-bar, presser-bar lifting meansconnected with said member and being effective to shift said presserbaraway from said work-support, and lost-motion mechanism associated withsaid member for forcing said toggle mechanism and said presserbarlifting means to be operated successively by a single continuousmovement of said member.

'7. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-bar, a spring for pressing saidpresser-bar toward said work-support, a manual control member,spring-disengaging means connected with said member for removing theforce of said spring from said presser-bar, presser-bar lifting meansconnected with said member and being effective to shift said presser-baraway from 'said work-support, and means including a Geneva stopmechanism associated with said member for timing the actions of saidspring-disengaging means and said presser-bar lifting means so that theymay be operated successively by a single continuous movement of saidmember. 8. A presser-mechanism for sewing machines having a frameincluding a work-support, comprising, a presser-bar, a spring forbiasing said presser-bar toward said work-support, means interposed inoperative relation between said spring and said presser-bar formultiplying the applied force of said spring and applying the resultantupon said presser-loana manual control member, springdisengaging meansconnected with. said member for removing the force of said spring fromsaid presser-bar, presser-bar lifting means connected with said memberand being effective to shift said presser-bar away from said worksupport, and means including a Geneva stop mechanism 'associated withsaid member for timing the actions of said spring-disengaging means andsaid presser-bar lifting means so that thei may be operated successivelyby a single continuous movement of said member.

9. A presser-mechanism for sewing machines having a frame including awrk-support, comprising, a presser-bar, a spring for urging 'saidpresser-bar toward said Work-support, a manual control member,spring-disengaging means connected with said member Vfor removing theforce of said spring from said presser-bar, presser-bar lifting meansconnected with said member and being adapted to shift said presser-baraway from said work-support, a rst Geneva stop mechanism interconnectedbetween said member and said spring-disengaging means, a second Genevastop mechanism interconnected between said member and said presser-barlifting means, and means interconnected between said member and said rstand second Geneva stops for timing the actions of saidspring-disengaging means and said presser-bar lifting means so that theymay be successively operated by a `single lcontinuous movement of saidmember.

10. A presser-mechanism for sewing machines having a frame including aworkesupport, a presser-bar, a spring for urging Vsaid pressenbar towardsaid work-support, means interposed in operative relation between saidspring and said presser-bar for multiplying the applied force of saidspring and applying the resultant upon said presser-bar,spring-disengaging means including a toggle mechanism effective toremove the force of said spring from said presser-bar, presser-barlifting means effective to shift said presser-bar away from saidWork-support, a pair of Geneva stop mechanisms, one of said Geneva stopmech anisms being associated in driving relation with saidspring-disengaging means, the other Geneva stop being associated indriving relation with said presser-bar lifting means, and a manualcontrol means connected to said Geneva stop mechanisms so assuccessively to actuate said spring-disengaging means and saidpresser-bar lifting means by a single continuous movement of said manualcontrol means.

11. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-bar, a lever having 'one end portionthereof in operative engagement with said presser-bar, spring means inengagement With the other end portion of said lever and being effectiveto bias said presser-bar toward said work-support, fulcrum means inengagement with an intermediate portion of said lever, a manual controlelement, spring-disengaging means connected with `said control elementfor removing the force of said spring from said pressn er-ban fulcrumshifting means connected with said control element for shifting saidfulcrum away from said lever, presser-bar lifting means connected withsaid control element for shifting said `presser-bar away from saidwork-support, and means associated with said control element for timingthe actions of said last three mentioned means so that they will besuccessively operated by a single continuous movement of said controlelement,

12. In a sewing machine having a frame including a head and awork-support, the combination lof a rpresser-bar slidably mounted withinsaidV head, a :spring for pressing said presser-bar toward saidwork-support, means comprising ya lever of the first order interposedbetween said spring and vpresser-bar for imposing upon said spring arange of movement materially longer than that of said presser-bar,force-multiplying means for removing the pressure of said spring fromsaid presser-bar, and manually controlled meansoperable upon removal ofsaid :spring vpressure from said presser-bar for shifting saidpresser-bar away from .said work-support.

13. In a sewing machine, the combination of a plurality of work-engagingfeet, a spring vfor pressing said feet upon the work, means interposedin operative relation between said spring and said feet for imposingupon said spring a range of movement Imaterially longer .than that ofeither of said feet, means for imparting mu tually alternating liftingmovements to said feet against the `force of said spring, manuallycontrolled means vincluding a force-multiplying mechanism for removingthe pressure of said spring from said feet, and means actuated by saidmanually controlled means and operable upon removal of said springpressure from said feet for shifting said feet away from saidwork-support.

14. .The combination in a sewing machine having a frame including .awork-support, a reciprocatory .presser-foot carrying bar, a feeding-footcarrying 'bar mounted for endwise reciprocatory and laterally joggingwork-feeding movements, means for Vreciprocally actuating Vsaid bars indi rections :toward and from said work-support, a spring for biasingeach of said bars toward said work-support, manually controlled meansincluding a .force-multiplying mechanism for removing the pressure ofsaid spring .from each of said bars, and means actuated by said manuallycontrolled means and operable `upon the removal of said spring lpressurefrom said bars for shifting said bars away from said work-support.

15. In a sewing machine, the combination of a plurality of work-engagingfeet, a swinging arm, a pivotal support for said arm, separateconnections between said arm and said feet, `a lever having one endthereof connected with said arm, a spring connected to the other end ofysaid -lever so as to force said feet against the work, a fulcrum membercooperatively associated with said lever and in engagement therewith ata point adjacent the arm so as to provide lthe spring with a range ofmovement materially longer than that of either of said feet, means toshift said fulcrum member away from said lever, and means effective uponthe removal of said fulcrum (from said lever to shift said feet awayfrom the Work.

v16. A presser-mechanism adapted to be used with a machine of the classdescribed having a presser-bar and a spring for biasing said presser-bartoward said work, said presser-mechanism comprising, a manual controlmemb'er, a first Geneva ,stop mechanism operatively connecting saidmanual rcontrol member with .said spring and being effective upon aninitial movement of said control member to remove the force of saidspring from said presser-bar, a second Geneva stop mechanism connectingsaid manual control member with said presser-bar and being effectiveupon the removal of said spring force from said presser-bar to raisesaid presser-bar off the work, and means associated with said controllever for sluiting said manual control member back into its initialposition upon the release of all manual control therefrom.

17. A presser-mechanism adapted to be used with a machine of the classdescribed having a presser-bar and a spring for biasing said presserbartoward said work, said presser-mechanism comprising, a manual controlmember, a first means operatively connecting said manual control memberwith said spring and being effective upon an initial movement of saidcontrol member to remove the force of said spring from said presser-bar,and a second means connecting said manual control member with saidpresser-bar and being effective upon the removal of said spring forcefrom said presser-bar to raise said presser-bar oif the work; said firstand second means each comprising, a driving element, a driven element, apin member carried by said driving element, and a complemental membercarried by said driven element coacting with said pin and shaped topermit said pin member to impart a driving impulse to said driven membersucceeded in one of said means and preceded in the other of said meansby a dwell.

18. In a sewing machine, the combination of a presser-bar, a spring tobias said presser-bar toward the work, a manual control member,force-multiplying means connected with said control member and beingeffective to remove the force of said spring from said presser-bar uponan initial movement of said control member, presser-bar lifting meansconnected with said presser-bar and being effective to shift saidpresser-bar away from the work upon the removal of the spring force fromsaid presser-bar, means associated with'said control member for shiftingthe latter into its initial position upon the release of all manualcontrol therefrom, and a pair of timing devices, one of said devicesbeing positioned between said control member and said force-multiplyingmeans, the other of said devices being positioned between said controlmember and said presser-bar lifting means, said pair of timing deviceseach comprising, a driving element, a driven element, a pin membercarried by said driving element, and a complemental member carried bysaid driven element coacting with said pin and shaped to permit said pinmember to impart a driving impulse to said driven member succeeded inone of said devices and preceded in the other of said devices by adwell.

19. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-member, a lever disposed inoperative engagement with said presser-member, fulcrum-means inengagement with said lever, an arm sustained by said frame, a springinterposed between said arm and said lever for biasing saidpresser-member toward said work-support, means for causing relativemovement between said lever and arm to relax said spring preparatory toshifting said presser-member, means for moving said fulcrum-means out ofengagement with said lever, and means for shifting said presser-memberaway from said worksupport.

20. A presser-mechanism for sewing machines having a frame including awork-support, comprising, a presser-member, a relatively rigid leverdisposed in operative engagement with said presser-member, a shiftablefulcrum having an operative position in engagement with said lever andan inoperative position out of engagement with said lever, a springconnected to said lever for normally biasing said presser-member towardsaid work-support, means for shifting said fulcrum from its operativeposition to its inoperative position preparatory to raising saidpressermember, and means for raising said pressermember from saidwork-support.

21. A presser-mechanism for sewing machines having a frame provided witha work-support, including, a presser-member, a lever disposed inoperative engagement with said presser-member, a shiftable fulcrumhaving an operative position in engagement with said lever and aninoperative position out of engagement with said lever, a springconnected to said lever for normally biasing said presser-member towardsaid work-support, means for moving said fulcrum into and out of itsoperative position, and means rendered effective by the movement of saidfulcrum for lowering and raising said presser-member relative to saidwork-support.

22. A presser-mechanism for sewing machines having a frame provided witha work-support, including, a presser-member, a lever disposed inoperative engagement with said presser-member, a fulcrum-elementturnable about an axis into and out of operative position with saidlever, a spring connected to said lever for normally biasing saidpresser-member toward said work-support, manually controlled means forturning said fulcrum-element into and out of its operative position andan arm operatively associated with said presser-member and connected t0said fulcrum-element so that the turning of said fulcrum-element intoand out of its operative position elfects a lowering and raising of saidpresser-member relative to said work-support.

23. A presser-mechanism for sewing machines having a frame provided witha work-support, comprising, a presser-member, a lever disposed inoperative engagement with said pressermember, a fulcrum-element turnableabout an axis into and out of operative position with said lever, an armsustained by said frame, a spring interposed between said arm and saidlever for biasing said presser-member toward said worksupport, rst meansfor effecting relative movement between said lever and said arm toremove the force of said spring from said presser-member, second meansoperated automatically by and in series with said first means forturning said fulcrum-element out of its operative position, and thirdmeans rendered effective by the turning movement of said fulcrum-elementfor raising said presser-member from said work-support.

FREDERICK F. ZEIER.

.REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,265,986 Ashworth May 14, 19181,279,112 Horton Sept. 17, 1918

